A few years ago, someone wrote an article about how they experienced skin light sensitivity as a result of consuming large amounts of buckwheat greens juice. We have enjoyed the delicious tang of buckwheat greens in moderation for many years without problems, but we don’t doubt that large quantities of buckwheat greens or buckwheat greens juice could cause the described condition. A wise approach would be moderation in all things, as we believe the issue with buckwheat greens is a question of dose. For example, some nutrients like salt, some vitamins and even water are vital in appropriate doses but can be harmful if too much is consumed. We feel buckwheat greens are no different.
From the article:
"I would like to make the disclaimer that I am not advising people to stop eating buckwheat. The Latin expression dosis sola facet venenum (the dose makes the poison) attributed to the ancient Romans could be applied here. A small quantity of buckwheat greens (or buckwheat lettuce as it is often called) in an individual diet could allow for healthy nutritional benefits without the negative effects of large amounts . . ."
Please read the article and make your own judgment.